package cn.tedu.coolshark.filter;

import cn.tedu.coolshark.entity.User;

import javax.servlet.*;
import javax.servlet.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebFilter(filterName = "MyFilter",urlPatterns = {"/insertProduct.html","/admin.html"})
public class MyFilter implements Filter {
    //当过滤器初始化时执行的方法
    public void init(FilterConfig config) throws ServletException {
    }

    //当过滤器销毁时执行的方法
    public void destroy() {
    }

    //当接收到请求时会执行的方法,需要在此方法中进行判断  是否允许访问Controller或静态资源文件
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        //将父类类型转换成子类类型
        HttpServletRequest st = (HttpServletRequest) request;
        HttpServletResponse se = (HttpServletResponse) response;
        //得到会话对象
        HttpSession session = st.getSession();
        //从会话对象中得到登录时保存的用户对象
        User user = (User) session.getAttribute("user");
        if(user!=null){//代表登录过
            chain.doFilter(request, response);//方行 允许访问资源
        }else{
            se.sendRedirect("/login.html");//重定向  让客户端重新向指定的地址发出请求
        }

        System.out.println("过滤器执行了");


    }
}
